As soon as the moral principles grow independent, they cease to be, in consequence, an element of social progress. They ossify, become a conservative element, an obstacle to progress. Thus can that happen in the human society which is impossible in the animal, morality can become, instead of an indispensable social bond, the means of an intolerable restraint on social life. That is also a reciprocal action, but not one in the sense of our anti-materialist moralists.
The contradictions between distinct moral principles and distinct social needs can arrive at a certain degree of intensity in primitive society; they then become, however, still greater with the appearance of class antagonism. If in the society without classes the adherence to particular moral principles is only a matter of habit, it only requires for them supervision that the force of habit be overcome. From now on the maintenance of particular moral principles becomes a matter of interest, often of a very powerful interest. And now appear, also weapons of force, of physical compulsion to keep down the exploited classes, and this means of compulsion is placed also at the service of "morality," to secure obedience to moral principles which are in the interest of the ruling classes.
The classless society needs no such compulsory weapons. Certainly, even in it the social instincts do not always suffice to achieve the observance by every individual of the moral code; the strength of the social impulses is very different in the different individuals, and just as different to that of the other instincts: those of self-maintenance and reproduction. The first do not always win the upper hand. But as a means of compulsion, of punishment for others, public opinion—the opinion of the society—suffices in such cases for the classless society. It does not create in us the moral law, the feeling of duty. Conscience works in us when no one sees us, and the power of public opinion is entirely excluded ; it can even, under circumstances, in a society filled with class antagonisms and contradictory moral codes, force us to defy public opinion.
